In self-assembly processes, components can be made to assemble without specifically placing the components in a particular configuration. The components assemble in a particular configuration because the desired configuration is the lowest energy state available to the system.
Terfort et al. (Three-dimensional self-assembly of millimetre scale components, Nature Vol 386, Mar. 13, 1997 pgs. 162-164) describe a process for self-assembly of microstructures by creating hydrophilic and hydrophobic surfaces. The hydrophobic surfaces adhere to one another and a liquid acts as a lubricant allowing the components to adjust their position to one another by lateral movement. The components can be wet with a photopolymerizable adhesive. After the system approaches equilibrium, the system is exposed to ultraviolet irradiation and the components are affixed into permanent form
U.S. Pat. No. 5,824,186 and related patents describe the use of a eutectic layer (gold, silver, solder) for bonding through a heating step that is subsequent to the transferring step.
The prior art also describes methods to accomplish the locking in of self-located objects which involve for example, the use of a UV polymerizable adhesive, use of a metal solder with the assembly done at a temperature high enough to melt the solder, or use of polymeric coatings for assembly that are hardened through heating or freezing the components in place. In each of these methods, after the self-location assembly step is complete, a further processing step must be carried out to lock the objects permanently in place. For the UV polymerizable adhesive, the system must be exposed to UV light for some period of time, and the assembly objects and coatings must be transparent to UV wavelengths. For systems which use solder, the system must be cooled to below the melting temperature of the solder. For thermally polymerized systems, the adhesive can be hardened only after assembly is complete.
The inventors are not aware of any system for self-assembly where the permanent adhesion occurs during the assembly process. The inventors are also not aware of any other technique that allows for the selective hardening of an adhesive as each individual part or component is located in or on an appropriate location of a substrate.